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Technical demonstrations

The technical demonstrations explore XtreemOS and some particularly interseting components in more depth. They can also be viewed as short XtreemOS tutorials.

Core demo scenario

This first part of core scenario shows administration of virtual organizations and basic job submission. It involves two actors: a grid administrator working on node core.xlab.si and a user working on his computer client.xlab.si. The grid contains the node resource.xlab.si.

The administrator starts with explaining the web-based XtreemFS and Scalaris status pages. The user shows his XteemFS home volume and copies some files from his local home directory to XtreemFS. He explains a simple job hello that he would like to submit. However, he is not a member of any VO yet, so he asks to join the demo-vo using the VOlife web interface. The administrator approves his request and also adds him to a group and role within this VO. The user downloads the certificate that proves his VO membership. He can now submit the job and show the output.



The second part continues with advanced administration tasks. A job with specific resource requirements is shown first. It cannot be submitted because no available resource has enough memory. The client node is thus added as a computational resource to demo-vo which requires cooperation of grid administrator and node (resource) administrator. The job is then successfully submitted. Monitoring the job during its execution is also shown. Command-line interface is used throughout.





XtreemFS

XtreemFS is global, distributed, replicated file system. It is used in XtreemOS to store and share data and applications.

The first demo video demonstrates the XtreemFS replication and failover with an unmodified MPlayer. A regular movie file stored on two XtreemFS OSDs (Object Storage Devices). is played As one OSD is disconnected, the user only senses a short pause (depending on the size of MPlayer buffer) before the XtreemFS client transparently switches to another replica.



The second demonstration shows how new replicas are created and how the on-demand replication strategy works.